Transparent conductive film roll and production method thereof, touch panel using it, and non-contact surface resistance measuring device

ABSTRACT

A transparent conductive film roll which has a transparent conductive layer on at least one surface thereof and has an excellent distribution uniformity of surface resistance in longitudinal and lateral directions thereof wherein the distribution uniformity D of surface resistance defined by the following expression (1) is 0.2 or less when the surface resistance of the transparent conductive layer is measured at a total of 33 points within the film roll, and therefore, is suitable especially for a large panel,  
       D =( Rmax−Rmin )/( Rmax+Rmin )  (1)  
     where Rmax and Rmin represent the maximum and minimum values of 33 surface resistance measurement values.

TECHNICAL FIELD

[0001] The present invention relates to a transparent conductive filmroll which is a roll of transparent conductive film, in which atransparent conductive layer is laminated on a plastic film, and aproduction method thereof, and a touch panel using the same and anon-contact surface resistance measuring device. More particularly, thepresent invention relates to a long transparent conductive film rollhaving a uniform surface resistance distribution in a longitudinaldirection thereof and in a lateral direction thereof, which is suitablefor a transparent electrode for a touch panel or an electroluminescencepanel which requires transparency and conductivity, particularly atransparent electrode for a large panel, and a touch panel using thesame and a non-contact surface resistance measuring device.

BACKGROUND ART

[0002] As a transparent conductive film, a film comprising a plasticfilm and a conductive material provided thereon is commonly used. As theconductive material, either organic or inorganic materials can be used.Inorganic materials are preferable in terms of both conductivity andtransparency. As the inorganic material, metals, such as gold, silverand the like, and metal oxides are preferable in terms of transparency.Among metal oxides, indium oxide, tin oxide, zinc oxide, and mixedoxides thereof are particularly preferable. Films in which theabove-described metal oxide is deposited on a plastic film using a vapordeposition method, an ion plating method, a sputtering method or a CVDmethod, are known.

[0003] Transparent conductive films are generally produced by an ionplating device or a sputtering device which roll up a film. Atransparent conductive film roll produced by the above-described deviceis cut by a slitter into pieces having a size of about 300 to 800 mm inwidth and about 10 to 1000 m in length, which are in turn rolled up by apaper tube or plastic core. Thus, the transparent conductive film isgenerally circulated in the form of a film roll. After a film roll inwhich a film is rolled up is cut into sheets, silver paste printing,dielectric printing or the like is performed on the film so that theresultant film is used as a transparent electrode for a tough panel oran electroluminescence panel.

[0004] In analog touch panels, the position of an input is recognizedand characters or symbols are displayed, assuming that the distributionof surface resistance of a transparent electrode thereof is uniform(“Gekkan Disupurei [Monthly Display”, September 1999, p. 82). Therefore,the surface resistance of a transparent conductive film used thereinneeds to be uniformly distributed at any position thereof. Also, in thecase of transparent electrodes of electroluminescence panels, atransparent electrode having a uniform surface resistance distributionis required to obtain uniform light emission intensity within the panel.In particular, as the size of an electroluminescence panel is increased,the higher degree of uniformity is required for the distribution ofsurface resistance of a transparent electrode thereof.

[0005] The distribution of surface resistance of a transparent electrodecan be made uniform as follows. A surface resistance measuring device isprovided in a rolled-up film forming device. The surface resistance of atransparent conductive layer is sequentially measured in-line whileforming the transparent conductive layer. Conditions for forming thetransparent conductive layer are regulated so that the surfaceresistance thereof is uniformly distributed.

[0006] An example of the above-described method includes a method forcontacting and sandwiching a transparent conductive film between twometal rollers and measuring the surface resistance between the rollers.However, in principle, this method can measure the distribution ofsurface resistance of a transparent conductive film in a longitudinaldirection thereof, but not the surface resistance distribution in alateral direction thereof. Concerning the surface resistancedistribution in a longitudinal direction thereof, if the tension of thefilm is not uniform, the contact between the metal rolls and thetransparent conductive layer is not uniform, leading to errors in themeasurement of the surface resistance.

[0007] There is also a method for measuring the surface resistance of atransparent conductive film in a lateral direction thereof, in whichthree or more metal rings are provided around an insulated roller (madeof silicone rubber or polytetrafluoroethylene) and the resistancebetween each metal ring is measured. However, a small protrusion isformed between the insulator and the metal ring, which is likely todamage the film surface.

[0008] Therefore, as a surface resistance measuring device which cansequentially measure the surface resistance distribution in a lateraldirection thereof and does not damage the film surface, a method formeasuring a coupled inductance between an electromagnetic induction coiland a conductive film (a method for applying magnetic field andmeasuring a resulting eddy current) is known (“Gekkan Disupurei [MonthlyDisplay”, September 1999, p. 88). In this method, however, aconsiderably high intensity of applied magnetic field is required forthe measurement of a conductive film having a surface resistance of 10Ω/□ or more. In this case, the spread of magnetic flux is large, leadingto the path line fluctuation of a substrate in a production process(vibration in a direction normal to a surface of the substrate). Thus, adistance between a sensor section and a conductive film to be measuredfluctuates and the coupled inductance is not constant. As a result, thein-line sequential measurement has large measurement errors.

[0009] Further, in this method, the magnetic permeability of a ferritecoil which functions as an eddy current generating section or an eddycurrent detecting section has a temperature dependency. The inductanceis changed in accordance with, if any, the fluctuation of thetemperature. Therefore, even if a high frequency voltage applied to thecoil is constant, an eddy current flowing through the conductive film ischanged, resulting in large measurement errors.

[0010] As described above, even if a general surface resistancemeasuring device is provided in a rolling up device, large measurementerrors make it considerably difficult to obtain a transparent conductivefilm roll having uniform surface resistance.

[0011] The present invention was made, taking the above-describedcircumstances into consideration. An object of the present invention isto provide a transparent conductive film roll having a uniform surfaceresistance distribution in a longitudinal direction thereof and in alateral direction thereof; a production method thereof; and a touchpanel produced using the same.

DISCLOSURE OF THE INVENTION

[0012] A transparent conductive film roll of the present invention isobtained by rolling up a plastic film having a transparent conductivelayer on at least one side thereof. A width thereof is 300 to 1300 mmand a length thereof is 10 to 1000 m. When the surface resistance (Ω/□)of the transparent conductive layer is measured at a total of 33 pointsincluding positions located at a middle in a lateral direction thereofand any positions located at a distance of from 25 to 100 mm fromlateral ends thereof, the positions being separated in intervals of{fraction (1/10)} of a full length in a longitudinal direction thereof,the distribution uniformity D of the surface resistance is 0.2 or less.The distribution uniformity D is represented by expression (1):

D=(Rmax−Rmin)/(Rmax+Rmin)  (1)

[0013] where Rmax and Rmin represent the maximum and minimum surfaceresistance values measured at the 33 points, respectively. The closer tozero the distribution uniformity D of the surface resistance, thesmaller the fluctuation of the surface resistance.

[0014] A touch panel of the present invention comprises a pair of panelplates having a transparent conductive layer. The panel plates aredisposed via a spacer so that the transparent conductive layers faceeach other. At least one of the panel plates is a transparent conductivefilm obtained by cutting the above-described transparent conductive filmroll.

[0015] A method of the present invention is provided for producing atransparent conductive film roll having a transparent conductive layeron at least one side thereof using a rolled-up film forming device. Therolled-up film forming device has anon-contact surface resistancemeasuring device therewithin. The surface resistance of the transparentconductive layer is sequentially measured in line while forming thetransparent conductive layer. Conditions for forming the transparentconductive layer are regulated so that the surface resistance thereof isuniformly distributed.

[0016] A non-contact surface resistance measuring device of the presentinvention mainly comprises an eddy current generating section which isplaced at a predetermined distance from the transparent conductivelayer, faces the transparent conductive layer and flows an eddy currentin the transparent conductive layer, an eddy current detecting sectionwhich is separated from the transparent conductive layer and detects theeddy current flowing through the transparent conductive layer, atemperature detecting section which detects a temperature of the eddycurrent generating section or the eddy current detecting section, and acalculating means which calculates a surface resistance of thetransparent conductive layer based on a result of detection by the eddycurrent detecting section and a result of detection by the temperaturedetecting section where a voltage applied to the eddy current generatingsection is constant. When the result of detection by the temperaturedetecting section is deviated from a reference temperature, thecalculating means calculates an amount of an increase or decrease in theeddy current caused by the deviation from the reference temperature andadds or subtracts the amount of the increase or decrease in the eddycurrent to or from the result of detection by the eddy current detectingsection to correct the value of the eddy current and calculates thesurface resistance of the transparent conductive layer based on thecorrected value of the eddy current.

[0017] The plastic film used as the substrate for the transparentconductive film roll of the present invention is obtained by extrudingan organic polymer in a molten or solution state and optionallystretching the polymer in a longitudinal and/or lateral directionsthereof, cooling and annealing the polymer.

[0018] Examples of such an organic polymer include polyethylenes,polypropylenes, polyethylene terephthalates,polyethylene-2,6-naphthalates, polypropylene terephthalates, nylon 6,nylon 4, nylon 6.6, nylon 12, polyimides, polyamideimides,polyethersulfanes, polyetheretherketones, polycarbonates, polyarylates,cellulose propionates, polyvinyl chlorides, polyvinylidene chlorides,polyvinyl alcohols, polyetherimides, polyphenylene sulfides,polyphenylene oxides, polystyrenes, syndiotactic polystyrenes,norbornene polymers, and the like.

[0019] Among these organic polymers, polyethylene terephthalates,polypropylene terephthalates, polyethylene-2,6-naphthalates,syndiotactic polystyrenes, norbornene polymers, polycarbonates,polyarylates, and the like are preferable. These organic polymers may beused as homopolymer or may be copolymerized with a small amount ofmonomers of other organic polymers. Also, these organic polymers may beblended with one or more kinds of other organic polymers.

[0020] The above-described plastic film needs to have an excellent levelof transparency in view of the visibility of a panel. Therefore, it ispreferable that particles, additives or the like which worsen thetransparency are not contained in the plastic film. However, the filmsurface preferably has an appropriate level of surface roughness in viewof handling ability (sliding ability, running ability, blocking ability,ability to purge accompanying air when rolling up, etc.) in producing aplastic film and unrolling or rolling a roll.

[0021] To meet mutually contradictory characteristics, a substrate filmhaving a layered structure is produced by a coating method orcoextruding method, where the thickness of the film is considerablysmall, i.e., 0.03 to 1 μm and particles are contained only in a surfacelayer. Among these methods, the coating method is preferable. This isbecause the coating method can produce a film thinner than that made bythe coextruding method, so that the adhesion between the plastic filmand a conducting layer can be satisfactory.

[0022] When a layered plastic film is used as a substrate, one or morekinds of particles may be contained in a surface layer thereof.Particles having a refractive index equal or close to that of acomponent resin of the plastic film and a binder resin of a coat layerthereof are preferable in view of the transparency thereof. For example,when a polyester-based resin is used as a binder resin in the substrateor the coat layer, 0.5 to 5.0% by weight of particles (e.g., silica,glass filler, mixed oxide such as alumina-silica, etc.) having anaverage diameter of 10 to 200 nm are preferably contained in the binderresin.

[0023] The thickness of the plastic film is preferably in the range ofmore than 10 μm and no more than 300 μm, particularly preferably in therange of from 70 to 260 μm. When the thickness of the plastic film is nomore than 10 μm, the mechanical strength is insufficient. In this case,particularly, when the plastic film is used in a touch panel, the filmis likely to be significantly deformed by a stylus input, resulting ininsufficient durability. When the thickness exceeds 300 μm, it isdifficult to roll up the film.

[0024] The surface of the above-described plastic film may be subjectedto surface activating treatment, such as corona discharge treatment,glow discharge treatment, flame treatment, ultraviolet irradiationtreatment, electron beam irradiation treatment, ozone treatment, or thelike, to an extent which does not impair the object of the presentinvention.

[0025] A curable resin cured material layer or an inorganic thin filmlayer may be provided between the substrate plastic film and thetransparent conductive layer so as to improve the adhesiveness of thetransparent conductive layer. The curable resin may not be particularlylimited as long as the resin is capable of being cured by applyingenergy, such as heating, ultraviolet irradiation, electron beamirradiation, or the like. Examples of the curable resin include siliconeresins, acrylic resins, methacrylic resins, epoxy resins, melamineresins, polyester resins, urethane resins, and the like. An ultravioletcurable resin is preferably a major component in view of productivity.

[0026] The transparent conductive layer used in the present invention isnot particularly limited as long as the transparent conductive layer ismade of a material having both transparency and conductivity. Examplesof the transparent conductive layer include a monolayer structure or alayered structure having two or more layers, which are made of indiumoxide, tin oxide, zinc oxide, indium-tin mixed oxides, tin-antimonymixed oxides, zinc-aluminum mixed oxides, indium-zinc mixed oxides,silver and silver alloys, copper and copper alloys, gold, or the like.Among them, indium-tin mixed oxides or tin-antimony mixed oxides arepreferable in view of environmental stability or circuit workability.

[0027] In order to adjust the surface resistance or the transparency,the transparent conductive layer may contain at least one of titaniumoxide, cerium oxide, tungsten oxide, niobe oxide, yttrium oxide,zirconium oxide, silicon oxide, zinc oxide, gallium oxide, aluminumoxide, antimony oxide, tantalum oxide, hafnium oxide, samarium oxide,and the like. The total amount of the inorganic oxide contents ispreferably 10% by weight or less with respect to the major component ofthe transparent conductive layer.

[0028] The thickness of the transparent conductive layer is preferablyin the range of from 4 to 800 nm, particularly preferably from 5 to 500nm. When the transparent conductive layer has a thickness of less than 4nm, it is difficult to produce a continuous thin film and thetransparent conductive layer tends not to have a satisfactory level ofconductivity. When the thickness is more than 800 nm, the transparencyis likely to be reduced.

[0029] Examples of a known method for forming a transparent conductivelayer of the present invention include a vacuum deposition method, asputtering method, a CVD method, an ion plating method, a sprayingmethod, and the like. Among these methods, an appropriate method may beselected depending on a required thickness.

[0030] Examples of the sputtering method include a typical sputteringmethod using an oxide target, a reactive sputtering method using a metaltarget, and the like. In this case, a reactive gas, such as oxygen,nitrogen or the like, maybe introduced, or a technique, such as ozoneaddition, plasma irradiation, ion assist or the like, may be used incombination with the sputtering method. A bias, such as direct current,alternating current, high frequency or the like, may be applied to thesubstrate to such an extent that the object of the present invention isnot impaired.

[0031] A monolayer or a multilayer made of a material having arefractive index different from that of the transparent conductive layermay be preferably provided between the transparent conductive layer andthe plastic film so as to reduce the light reflectance of thetransparent conductive film at a surface of the transparent conductivelayer and improve the light transmittance thereof. In the case of themonolayer, a material having a refractive index smaller than that of thetransparent conductive layer is preferably used. In the case of amultilayered structure having two or more layers, a layer adjacent tothe plastic film may be made of a material having a refractive indexgreater than that of the plastic film while a layer underlying thetransparent conductive layer may be made of a material having arefractive index smaller than that of the transparent conductive layer.

[0032] The above-described material for low reflection treatment is notparticularly limited to organic or inorganic materials as long as thematerial satisfies the above-described relationship between therefractive indexes. Examples of the material include dielectricmaterials, such as CaF₂, MgF₂, NaAlF₄, SiO₂, ThF₄, ZrO₂, Nd₂O₃, SnO₂,TiO₂, CeO₂, ZnS, In₂O₃, and the like.

[0033] A transparent conductive film roll of the present invention has auniform surface resistance distribution in longitudinal and lateraldirections thereof, where a distribution uniformity D of the surfaceresistance is 0.2 or less, the distribution uniformity D beingrepresented by expression (1):

D=(Rmax−Rmin)/(Rmax+Rmin)  (1).

[0034] In a transparent conductive film roll produced by theabove-described material and method, the surface resistance distributionis made uniform in longitudinal and lateral directions thereof by usingan in-line and non-contact surface resistance measuring device describedbelow which is provided in a rolled-up film forming device in the stepof providing a transparent conductive layer.

[0035] A configuration of the non-contact surface resistance measuringdevice will be described with reference to FIG. 1.

[0036] The non-contact surface resistance measuring device comprises aplurality (n) of eddy current sensors 3 which are placed at apredetermined distance from a conductive layer 2 on a substrate 1 andfaces the conductive layer 2. The eddy current sensor 3 comprises aneddy current generating section 3A which flows an eddy current in theconductive layer 2, and an eddy current detecting section 3B (integratedwith the eddy current generating section 3A) which is separated from theconductive layer 2 and detects the eddy current flowing through theconductive layer 2. A temperature sensor 4A (corresponding to atemperature detecting section) which detects a temperature of the eddycurrent sensor 3 and a separation distance sensor 4B which detects thedistance between the eddy current sensor 3 and the conductive layer 2are integrated with the eddy current sensor 3. The non-contact surfaceresistance measuring device further comprises a computer 7(corresponding to a calculation means) which calculates the surfaceresistance of the conductive layer 2 based on the results of detectionby the eddy current detecting section 3B and the results of detection bythe temperature sensor 4A and the separation distance sensor 4B.

[0037] The eddy current sensor 3, the temperature sensor 4A and theseparation distance sensor 4B are each connected to a sensor amplifier6. The sensor amplifier 6 comprises a high frequency oscillator, an A/Dconverting means which converts an analog signal of an eddy current to adigital signal, an A/D converting means which converts an analog signalcorresponding to a separation distance between the conductive layer 2and the sensor 3 to a digital signal, and an A/D converting means whichconverts an analog signal corresponding to a temperature to a digitalsignal. The high frequency oscillator applies a high frequency to theconductive layer and detects an eddy current flowing through theconductive layer.

[0038] Preferably, the sensor 4B which detects a separation distancebetween the conductive layer 2 and the sensor 3 is a displacement sensorof capacitance type, ultrasonic type, laser type, photoelectric type orthe like. The means which calculates the surface resistance of aconductive layer based on a digital signal.

[0039] A method of flowing an eddy current in a conductive layer isachieved by providing an eddy current generating section and an eddycurrent detecting section so that they are located a predetermineddistance from the conductive layer and face the conductive layer, or bysandwiching the conductive film by an eddy current generating sectionand an eddy current detecting section. For example, a high frequencyvoltage is applied to a coil, such as a ferrite coil or the like, whichfunctions as an eddy current generating section, and the coil is movedclose to a conductive layer, or a conductive film is sandwiched by thecoil to flow an eddy current in the conductive layer due to highfrequency inductive coupling.

[0040] When a high frequency voltage is constant, an eddy currentflowing in the conductive layer is inversely proportional to the surfaceresistance of the conductive layer. Therefore, if a calibration curve ispreviously provided for a relationship between eddy current and surfaceresistance, a surface resistance can be obtained at a separationdistance (reference point).

[0041] In principle, an eddy current tends to be decreased with anincrease in a separation distance between a conductive layer and asensor. A pre-prepared calibration curve is provided for a relationshipbetween eddy current and a separation distance. Specifically, a meanswhich detects the separation distance between a conductive layer and asensor is used to obtain a separation distance. A difference between theseparation distance and a reference point is obtained. A correctionvalue is calculated for an eddy current based on the calibration curve.The correction value is subtracted when the separation distance betweena conductive layer and a sensor is smaller than the reference point,while the correction value is added when the separation distance betweena conductive layer and a sensor is greater than the reference point.Thus, the surface resistance of a conductive layer can be accuratelycalculated at any separation distance between the conductive layer and asensor. The calculation of the surface resistance of a conductive layeris sequentially performed in a production process of the conductivelayer in accordance with the operation cycles of a computer.

[0042] In principle, the magnetic permeability of a coil which functionsas an eddy current generating section or an eddy current detectingsection has a temperature dependency. Therefore, an eddy current ischanged in accordance with, if any, temperature fluctuation. There is apositive correlation between eddy current and magnetic permeability.There are both positive and negative temperature dependencies of themagnetic permeability of a coil depending on the type of the coilmaterial. Specifically, the positive dependency means that the magneticpermeability is increased with an increase in the temperature Thenegative dependency means that the magnetic permeability is decreasedwith an increase in the temperature.

[0043] Therefore, when the result of detection by the temperaturedetecting section is deviated from the reference temperature, thecalculating means obtains the amount of an increase or decrease in aneddy current caused by the deviation from the reference temperaturebased on the temperature dependency of a selected coil material. Inaddition, the amount of an increase or decrease in the eddy current issubtracted from or added to the detection result by the eddy currentdetecting section to correct the value of the eddy current. The surfaceresistance is calculated based on the corrected value of the eddycurrent.

[0044] In this case, it is important to previously prepare a calibrationcurve for a relationship between temperature fluctuations and correctededdy current amounts.

[0045] Thus, the surface resistance of a conductive layer is calculatedbased on a previously prepared calibration curve. Therefore, even whenthe temperature of an eddy current generating section fluctuates, anerror is unlikely to occur in the measurement value of the surfaceresistance of a conductive layer.

[0046] By providing a plurality of eddy current generating sections andeddy current detecting sections in a lateral direction of a conductivelayer in a production process thereof, the surface resistance of theconductive layer in the lateral direction can be accurately measuredeven if there is a temperature distribution (uneven temperature) in thelateral direction due to the large width.

[0047] The eddy current sensor 3, the temperature sensor 4A and theseparation distance sensor 4B are connected via a sensor cable 5 to thesensor amplifier 6. A CRT 8 which displays a measurement result, aprinter 9 which produces printed outputs of the measurement result, andan alarm device 10 which reports to an operator that a measured surfaceresistance exceeds a predetermined range, or an abnormality, areprovided.

[0048] The sensor amplifier 6 is provided with a high frequencyoscillator, a first A/D converter which converts an analog signal of aneddy current to a digital signal, and a second A/D converter whichconverts an analog signal corresponding to the temperature to a digitalsignal.

[0049] The computer 7 processes data based on digital signals obtainedby the first and second A/D converters. When a detection result of thetemperature sensor 4 is deviated from the reference temperature, thecomputer 7 obtains the amount of an increase or decrease in an eddycurrent caused by the deviation from the reference temperature, adds orsubtracts the amount of the increase or decrease in the eddy current toor from a detection result of the eddy current detecting section 3B tocorrect the value of the eddy current, and calculates the surfaceresistance of the conductive layer 2 based on the corrected value of theeddy current. This calculation method will be described in detail below.

[0050] In a production process for the conductive layer 2, a pluralityof non-contact surface resistance measuring devices are provided in alateral direction of the conductive layer 2 or the non-contact surfaceresistance measuring device is continuously reciprocated in the lateraldirection of the conductive layer 2. Thereby, a surface resistancedistribution in the lateral direction of the conductive layer 2 of atransparent conductive film roll or a trend (changes over time) of thesurface resistance in a longitudinal direction of the conductive layer 2can be obtained by the computer 7.

[0051] Next, an operation of the non-contact surface resistancemeasuring device will be described below.

[0052] (1) The eddy current sensor 3, the temperature sensor 4A and theseparation distance sensor 4B are placed such that the eddy currentgenerating sections 3A faces the conductive layer 2 on the substrate 1at a predetermined distance of several millimeters from the conductivelayer 2, or such that the eddy current generating sections 3A sandwichthe substrate 1.

[0053] (2) A high frequency is applied from the sensor amplifier 6 tothe eddy current generating section 3A of the eddy current sensor 3 togenerate an eddy current in the conductive layer 2 due to high frequencyinduction coupling.

[0054] (3) When the applied high frequency voltage is controlled to beconstant, an eddy current flowing in the conductive layer 2 is inverselyproportional to the surface resistance of the conductive layer 2.Therefore, if a calibration curve is previously provided for arelationship between eddy current and surface resistance as shown inFIG. 2, a surface resistance of an unknown conductive layer 2 can beobtained at the reference temperature where the conductive layer 2 andthe eddy current generating section 3A are separated at thepredetermined distance.

[0055] (4) An eddy current is increased if the temperature dependency ofa coil material is a positive dependency. Thus, a surface resistancetends to be small. Therefore, the detection result of the eddy currentdetecting section 3B is corrected based on the previously preparedcalibration curve for the relationship between surface resistance andtemperature as shown in FIG. 3.

[0056] The correction method will be described in detail below.

[0057] For example, it is assumed that a conductive layer has a surfaceresistance of 50 Ω/□ at a reference temperature of 25° C. If thetemperature is increased to 30° C., the surface resistance is about 40Ω/□, so that the measured value is decreased by 20% from the actualsurface resistance. This relationship is represented by expression (2)below.

Y=−0.0458X ²+0.2404X+72.95  (2)

[0058] where the X axis represents ambient temperature (° C.) and the Yaxis represents the measured value of the surface resistance (Ω/□).

[0059] For example, if 30 (° C.) is substituted for X in expression (2),Y is calculated to be 38.9 (Ω/□). A surface resistance is 50 Ω/□ at areference temperature of 25° C. Therefore, a correction amount is 11.1Ω/□. The correction amount is added to Y, resulting in a measurementresult of 50 Ω/□.

[0060] Conversely, if an ambient temperature is decreased to 20° C., 20(° C.) is substituted for X in expression (2). In this case, Y=59.4(Ω/□). Therefore, a correction amount is 9.4 Ω/□. The correction amountis subtracted from Y, resulting in a measurement result of 50 Ω/□.

[0061] The addition and subtraction of a correction amount arepreviously determined depending on the temperature dependency of amaterial for a conductive layer. With this correction technique, anerror in surface resistance measurement can be reduced even iftemperature fluctuates.

[0062] Thus, an accurate correction value can be obtained by previouslypreparing a calibration curve as shown in FIG. 3 for the conductivelayer 2 having known surface resistance.

[0063] (5) A surface resistance tends to be decreased with an increasein the separation distance between the eddy current sensor and theconductive layer. The calculation result obtained in (4) is correctedbased on a calibration curve for the relationship between surfaceresistance and separation distance shown in FIG. 4.

[0064] The surface resistance of the conductive layer 2 is displayed onthe CRT 6 by the computer 7 using any software. The surface resistanceis used as a measured value or a graph in data processing. The surfaceresistance is sequentially measured in line. The surface resistance isoptionally printed out by the printer 9.

[0065] The calculation of the surface resistance of the conductive layer2 can be sequentially performed in a production process of theconductive layer 2 in accordance with the operation cycles of thecomputer 7.

[0066] By feeding the measurement result of the surface resistance backto the alarm device 10 or a production process, the surface resistancecan be controlled in production of a transparent conductive film roll.Thereby, the quality and productivity in production process can beimproved.

[0067] By integrating the eddy current sensor 3, the temperature sensor4A and the separation distance sensor 4B together, the eddy current andthe temperature can be measured at substantially the same point.Thereby, measurement accuracy can be improved.

[0068] Other preferred embodiments of the non-contact surface resistancemeasuring device will be described below.

[0069] In a small production device in which the width of the conductivelayer 2 is from about 300 to 500 mm during a production process, atemperature distribution (uneven temperature) in a lateral direction isrelatively small and it is considered that temperature fluctuationoccurs substantially uniformly. When such a small production device isused to produce the conductive layer 2, it is possible that only asingle temperature sensor 4A is provided for a plurality of eddy currentsensors 3.

[0070] Specifically, the number of the temperature sensors 4 is madesmaller than the number of the eddy current generating sections 3A,thereby making it possible to suppress the cost of the temperaturesensor 4 to a low level.

[0071] It is preferable that the temperature sensor 4 has a highresolution and a satisfactory level of accuracy or responsiveness. Ifthe resolution is 0.2° C. or less and the accuracy is ±3% or less, amore accurate measurement result can be obtained.

[0072] The eddy current sensor 3 and the temperature sensor 4 may beprovided separately. The eddy current generating section 3A and the eddycurrent detecting section 3B may be provided separately and the eddycurrent generating section 3A is provided on the side of the conductivelayer 2 while the eddy current detecting section 3B and the temperaturesensor 4 are provided on the side of the substrate 1.

[0073] If a calibration curve is drawn based on data measured in therange of from 10° C. to 40° C. in 1° C. steps, a more accurate resultcan be obtained, though a temperature range used for correction is notlimited to the values described in the embodiments. It is preferable topreviously prepare a calibration curve indicating a relationship betweensurface resistance and temperature for each product sample.

[0074] The temperature sensor 4 can be composed of a temperature sensor,such as a thermocouple sensor, a resistance sensor, a thermocouple, aninfrared sensor or the like.

[0075] As the computer 7, a panel computer, a personal computer, afactory computer or the like can be used.

[0076] The numbers of the eddy current generating sections 3A, the eddycurrent detecting sections 3B and the temperature sensors 4 are notlimited to the values described in the above-described embodiments andmay be changed as appropriate.

[0077] The transparent conductive film roll of the present invention iscut by a slitter into pieces having a width of from about 300 to 800 mmand a length of from about 10 to 1000 m. The film is subjected to silverpaste printing, dielectric printing or the like, resulting in atransparent electrode for used in a touch panel or electroluminescencepanel.

[0078]FIG. 11 shows an exemplary analog stylus input touch panelcomprising a transparent conductive film obtained by cutting atransparent conductive film roll of the present invention. This touchpanel comprises a pair of panel plates having a transparent conductivelayer, which are disposed via a spacer so that the transparentconductive layers are opposed to each other, where at least one of thepanel plates is a transparent conductive film obtained by cutting atransparent conductive film roll of the present invention.

[0079] When a stylus is used to input a character or pattern on thetouch panel, a stylus pressure allows the opposing transparentconductive layers to contact each other, resulting in an electrically ONstate. Therefore, the position of the stylus can be detected on thetouch panel. By detecting the position of the stylus sequentially andaccurately, characters can be recognized from the trace of the stylus.

[0080] In this case, a transparent conductive film obtained by cutting atransparent conductive film roll of the present invention is provided ona panel plate which contacts a stylus. A surface resistance issubstantially uniform in longitudinal and lateral directions of thetransparent conductive film. Therefore, a stable touch panel having asmall character or pattern recognition deviation rate can be obtained nomatter what portion of the transparent conductive film roll is used.

[0081] Alternatively, a transparent conductive film obtained by cuttinga transparent conductive film roll of the present invention is providedon both panels of an analog stylus input touch panel. A transparentresin sheet is provided via an adhesive agent on a surface of thetransparent conductive film on which a conductive layer is notdeposited. Thus, a transparent conductive layered sheet for use in afixed electrode for a touch panel is obtained. By using a fixedelectrode made of a resin instead of one made of glass, a touch panelwhich is light and is difficult to break due to shock can be produced.

[0082] The above-described adhesive agent is not particularly limited aslong as it has transparency. Preferably examples of the adhesive agentinclude acrylic-based adhesive agents, silicone-based adhesive agents,rubber-based adhesive agents, and the like. The thickness of theadhesive agent is preferably in the range of from 1 to 100 μm, though itis not particularly limited. When the adhesive agent has a thickness ofless than 1 μm, it is difficult to obtain adhesiveness without anypractical problem. When the adhesive agent has a thickness of more than100 μm, the adhesive agent is not preferable in view of productivity.

[0083] The transparent resin sheet attached via the adhesive agent isused to provide a mechanical strength equal to that of glass. Thetransparent resin sheet preferably has a thickness of from 0.05 to 5 mm.When the transparent resin sheet has a thickness of less than 0.05 mm,the mechanical strength thereof is not satisfactory compared to that ofglass. When the transparent resin sheet has a thickness of more than 5mm, the transparent resin sheet is too thick to be suitable for a touchpanel. Materials for the above-described transparent plastic film can beused as materials for the transparent resin sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0084]FIG. 1 is a diagram for explaining a configuration of anon-contact surface resistance measuring device.

[0085]FIG. 2 is a diagram for explaining a calibration curve indicatinga relationship between eddy current and surface resistance.

[0086]FIG. 3 is a diagram for explaining a calibration curve indicatinga relationship between temperature and surface resistance.

[0087]FIG. 4 is a diagram for explaining a calibration curve indicatinga relationship between eddy current and separation distance.

[0088]FIG. 5 is a diagram for explaining a surface resistancedistribution in a slit roll in Example 1.

[0089]FIG. 6 is a diagram for explaining a surface resistancedistribution in a slit roll in Example 2.

[0090]FIG. 7 is a diagram for explaining a surface resistancedistribution in a slit roll in Example 3.

[0091]FIG. 8 is a diagram for explaining a surface resistancedistribution in a slit roll in Example 4.

[0092]FIG. 9 is a diagram for explaining a surface resistancedistribution in a slit roll in Comparative Example 1.

[0093]FIG. 10 is a diagram for explaining a surface resistancedistribution in a slit roll in Comparative Example 2.

[0094]FIG. 11 is a diagram for explaining an output shape of the touchpanel of Example 1.

[0095]FIG. 12 is a diagram for explaining an output shape of the touchpanel of Comparative Example 1.

[0096]FIG. 13 is a cross-sectional view of the touch panel of Example 1.

[0097]FIG. 14 is a diagram for explaining a surface resistancedistribution in a slit roll in Example 5.

DESCRIPTION OF REFERENCE NUMERALS

[0098]1 substrate

[0099]2 conductive layer

[0100]3A eddy current generating section

[0101]3B eddy current detecting section

[0102]4A temperature sensor

[0103]4B separation distance sensor

[0104]5 sensor cable

[0105]6 sensor amplifier

[0106]7 computer

[0107]8 CRT

[0108]9 printer

[0109]10 alarm device

[0110]11 communication cable

[0111]12 CRT cable

[0112]13 printer cable

[0113]14 control cable

[0114]15 pattern recognized by a touch panel

[0115]16 transparent conductive film

[0116]17 plastic film

[0117]18 transparent conductive layer

[0118]19 glass plate

[0119]20 beads

EXAMPLES

[0120] Hereinafter, the present invention will be described by way ofillustrative examples and comparative examples, though the presentinvention is not limited to the examples below. Characteristics oftransparent conductive film rolls and touch panels obtained in theexamples were assessed by a method described below.

[0121] (1) The Surface Resistance of a Transparent Conductive Layer

[0122] The surface resistance of a transparent conductive layer wasmeasured by a 4-pin probe method using a surface resistance measuringdevice (Lotest AMCP-T400 manufactured by Mitsubishi Petrochemical) inaccordance with JIS-K7194, where measurement was performed at pointswhich were located at a middle portion in a lateral direction of a slitroll of transparent conductive film and points which were located at adistance of 200 mm from the middle portion to the right and left, andthese points were separated in 10 mm intervals in a longitudinaldirection.

[0123] Specifically, the surface resistance of the slit roll wasmeasured at 33 points (3 points in the lateral direction×10 points inthe longitudinal direction) in a slit roll. The maximum and minimumvalues of 33 measurement values were represented by Rmax and Rmin,respectively. These values were used to calculate the distributionuniformity D of the surface resistance (=(Rmax−Rmin)/(Rmax+Rmin)). Thiscalculation was performed for a total of 16 slit rolls.

[0124] (2) The Pattern Recognition Deviation Rate of a Touch Panel

[0125] Five circles having a diameter of 40 mm were written on a touchpanel produced as described above using an X-Y plotter (DXY-1150Amanufactured by Roland). The tip of a pen of the plotter had a size of0.8 mmΦ and was made of polyacetal and the pen load was 0.6 N. Signalswere read from the silver paste and it was assessed whether or not thecircles were correctly recognized. A pattern recognition deviation rate(%) was calculated by (|r1−r0|/r0)×100, where the length of the majoraxis of a recognized mark is represented by r1 and the diameter of thewritten circle is represented by r0 (=40 mm). The pattern recognitiondeviation rate was calculated for the five written points. The highestdeviation rate was defined as the pattern recognition deviation rate ofthe touch panel.

Example 1

[0126] A sputtering and rolling up device comprising non-contact surfaceresistance measuring devices incorporating a temperature sensor and aseparation distance sensor as shown in FIG. 1 was used and an ITO target(containing 10% by weight of tin oxide, manufactured by Mitsui Miningand Smelting) was employed. Note that the non-contact surface resistancemeasuring device was provided at three points: a middle portion in alateral direction of a film; and at a distance of 500 mm from the middleportion to the right and left. A PET film roll having a size of 1300 mmin width, 850 m in length and 188 μm in thickness and having anadhesion-modified layer on one side thereof (A4100 manufactured by ToyoBoseki) was unrolled to provide a substrate. Next, a transparentconductive layer was formed on the adhesion modified surface of the PETfilm.

[0127] Conditions for forming the transparent conductive layer were asfollows: a pressure was 0.4 Pa in sputtering; the flow rate of Ar was200 sccm; and the flow rate of oxygen was 3 sccm. A power of 3 W/cm² wasapplied to a target using RPG100 (manufactured by Japan ENI). In thiscase, a positive voltage pulse having a pulse width of 2 μsec and apulse frequency of 100 kHz was applied to suppress the occurrence ofabnormal electric discharge.

[0128] Note that the temperature dependency and separation distancedependency of the eddy current sensor were previously measured toprepare a calibration curve. The feed speed of the film and the flowrate of oxygen were adjusted based on the calibration curve whilesequentially monitoring the measurement results of the eddy current-typesurface resistance measuring device so that the center of the surfaceresistance of the film was located at 250 Ω/□. The thickness of thetransparent conductive layer was from 22 to 27 nm at the time ofproduction of a transparent conductive film roll. Further, at the timeof production of the transparent conductive film roll, the surfaceresistance value of the conductive layer was output over 100 m atpositions which were located at the middle portion in a lateraldirection thereof, positions which were located at a distance of 500 mmfrom the middle portion to the right, and positions which were locatedat a distance of 500 mm from the middle portion to the left, and thesepositions were separated in 10 m intervals in a longitudinal directionthereof. The measurement results by the eddy current-type surfaceresistance measuring device are shown in FIG. 5. The distributionuniformity of the surface resistance D of the conductive film was 0.03.

[0129] The resultant transparent conductive film roll was slit into 16slit rolls each having a width of 600 mm and a length of 100 m. Theassessment results of the resultant transparent conductive film roll areshown in Table 1.

[0130] A200 mm×300 mm rectangle of transparent conductive film was cutout from the slit roll of transparent conductive film. The rectangulartransparent conductive film was used as one panel plate and a silverpaste was printed on opposite ends thereof (sides having a length of 200mm). A transparent conductive glass (S500 manufactured by Nippon Soda)having a 20-nm thick indium-tin mixed oxide thin film (tin oxidecontent: 10% by weight), which had been provided on the glass substrateby plasma CVD, was cut into a 200 mm×300 mm rectangle as the other panelplate. A silver paste was printed on opposite ends of the glass panel(sides having a length of 300 mm). The two panel plates were disposedvia epoxy beads having a diameter of 30 μm so that the transparentconductive layers faced each other, to produce a touch panel. FIG. 13shows a cross-sectional view of the resultant touch panel. The result ofassessment of the touch panel is shown in Table 2 and FIG. 11.

Example 2

[0131] A PET film (HC101 manufactured by Toyo Boseki) having a clearhard coating layer having a thickness of 192 μm on one side thereof wasused as a plastic film. A transparent conductive film roll and a touchpanel were obtained as in Example 1, except that a transparentconductive layer was formed on the other side with respect to the hardcoat layer. The results are shown in Tables 1 and 2. As in Example 1, atthe time of production of the transparent conductive film roll, thesurface resistance value of the conductive layer was output over 100 mat positions which were located at the middle portion in a lateraldirection thereof, positions which were located at a distance of 500 mmfrom the middle portion to the right, and positions which were locatedat a distance of 500 mm from the middle portion to the left, and thesepositions were separated in 10 m intervals in a longitudinal directionthereof. The measurement results by an eddy current-type surfaceresistance measuring device are shown in FIG. 6. The distributionuniformity of the surface resistance D of the conductive film was 0.09.

Example 3

[0132] A photopolymerization initiator-containing acrylic resin (SeikaBeam EXF-01J manufactured by Dainichiseika Colour & Chemicals Mfg.) wasadded to a mixed solvent of toluene and MEK (8:2 by weight) to a solidconcentration of 50% by weight. The mixture was stirred to afford ahomogeneous solution. Thus, application solution A was prepared.

[0133] Next, a PET film roll having a size of 1300 mm in width, 850 m inlength and 188 μm in thickness and having an adhesion-modified layer onone side thereof (A4100 manufactured by Toyo Boseki) was unrolled.Application solution A was applied to the adhesion modifying layer ofthe film to a thickness of 5 μm by Mayer bar, followed by drying at 80°C. for 1 min. The film was then irradiated with ultraviolet light usingan ultraviolet irradiating device (UB042-5AM-W manufactured byEyegraphics) (light amount: 300 mJ/cm²) to cure the applied film. Inaddition, heat treatment was performed at 180° C. for 1 min to reducethe volatile component. The PET film roll having the cured layer on oneside thereof was rolled up. The roll was prepared as a substrate.

[0134] The PET film roll having the cured layer on one side thereof wasused as a substrate as in Example 1 to obtain a transparent conductivefilm roll and a touch panel, except that a transparent conductive layerwas formed on a surface of the cured layer. The results are shown inTables 1 and 2.

[0135] As in Example 1, at the time of production of the transparentconductive film roll, the surface resistance value of the conductivelayer was output over 100 m at positions which were located at themiddle portion in a lateral direction thereof, positions which werelocated at a distance of 500 mm from the middle portion to the right,and positions which were located at a distance of 500 mm from the middleportion to the left, and these positions were separated in 10 mintervals in a longitudinal direction thereof. The measurement resultsby an eddy current-type surface resistance measuring device are shown inFIG. 7. The distribution uniformity of the surface resistance D of theconductive film was 0.02.

Example 4

[0136] A transparent conductive film roll and a touch panel wereproduced as in Example 1, except that the feed speed of the film and theflow rate of oxygen were adjusted so that the center of the surfaceresistance of the film was located at 1000 Ω/□ using a tin-antimonymixed oxide (ATO) target (containing 5% by weight of antimony oxide,manufactured by Mitsui Mining And Smelting) instead of ITO target, andthe flow rate of oxygen was changed from 3 sccm to 5 sccm. The resultsare shown in Tables 1 and 2. The thickness of the transparent conductivelayer was from 95 to 110 nm at the time of production of the transparentconductive film roll.

[0137] As in Example 1, at the time of production of the transparentconductive film roll, the surface resistance value of the conductivelayer was output over 100 m at positions which were located at themiddle portion in a lateral direction thereof, positions which werelocated at a distance of 500 mm from the middle portion to the right,and positions which were located at a distance of 500 mm from the middleportion to the left, and these positions were separated in 10 mintervals in a longitudinal direction thereof. The measurement resultsby an eddy current-type surface resistance measuring device are shown inFIG. 8. The distribution uniformity of the surface resistance D of theconductive film was 0.10.

Example 5

[0138] A transparent conductive film roll and a touch panel wereproduced as in Example 1, except that a non-contact surface resistancemeasuring device incorporating a temperature sensor and a separationdistance sensor is continuously reciprocated in a lateral direction of aconductive film to measure the surface resistance of the conductive filmat three points: a middle portion in a lateral direction of the film;and at a distance of 500 mm from the middle portion to the right andleft, instead of providing three non-contact surface resistancemeasuring devices at separated positions on the conductive film of thetransparent conductive film. The results are shown in Tables 1 and 2.

[0139] As in Example 1, at the time of production of the transparentconductive film roll, the surface resistance value of the conductivelayer was output over 100 m at positions which were located at themiddle portion in a lateral direction thereof, positions which werelocated at a distance of 500 mm from the middle portion to the right,and positions which were located at a distance of 500 mm from the middleportion to the left, and these positions were separated in 10 mintervals in a longitudinal direction thereof. The measurement resultsby an eddy current-type surface resistance measuring device are shown inFIG. 14. The distribution uniformity of the surface resistance D of theconductive film was 0.03.

Comparative Example 1

[0140] Comparative Example 1 was the same as Example 1, except that eddycurrent-type surface resistance measuring devices which did not comprisea temperature sensor and a separation distance sensor were used(provided at a total of three points: a middle portion in a lateraldirection of the film; and at a distance of 500 mm from the middleportion to the right and left). The results are shown in Tables 1 and 2and FIG. 12.

[0141] As in Example 1, at the time of production of the transparentconductive film roll, the surface resistance value of the conductivelayer was output over 100 m at positions which were located at themiddle portion in a lateral direction thereof, positions which werelocated at a distance of 500 mm from the middle portion to the right,and positions which were located at a distance of 500 mm from the middleportion to the left, and these positions were separated in 10 mintervals in a longitudinal direction thereof. The measurement resultsby the eddy current-type surface resistance measuring device are shownin FIG. 9. The distribution uniformity of the surface resistance D ofthe conductive film was 0.22.

Comparative Example 2

[0142] Comparative Example 2 was the same as Example 1, except that amonitor for calculating the surface resistance of a film based on aresistance value between two insulation free rolls was used instead ofeddy current-type surface resistance measuring devices. The results areshown in Tables 1 and 2.

[0143] As in Example 1, at the time of production of the transparentconductive film roll, the surface resistance value of the conductivelayer was output over 100 m at positions which were located at themiddle portion in a lateral direction thereof, positions which werelocated at a distance of 500 mm from the middle portion to the right,and positions which were located at a distance of 500 mm from the middleportion to the left, and these positions were separated in 10 mintervals in a longitudinal direction thereof. The measurement resultsby an eddy current-type surface resistance measuring device are shown inFIG. 10. The distribution uniformity of the surface resistance D of theconductive film was 0.33. TABLE 1 Surface resistance distributionuniformity D of Slit conductive film roll Example Example ExampleExample Example Comparative Comparative No. 1 2 3 4 5 Example 1 Example2 1 0.03 0.09 0.02 0.10 0.03 0.22 0.33 2 0.03 0.11 0.04 0.12 0.03 0.230.32 3 0.05 0.05 0.06 0.16 0.05 0.26 0.29 4 0.02 0.12 0.02 0.17 0.020.34 0.25 5 0.06 0.06 0.05 0.12 0.06 0.23 0.33 6 0.08 0.08 0.07 0.180.08 0.25 0.29 7 0.03 0.13 0.09 0.12 0.03 0.36 0.36 8 0.05 0.15 0.020.16 0.05 0.24 0.28 9 0.04 0.06 0.09 0.18 0.04 0.21 0.26 10 0.08 0.160.10 0.11 0.08 0.36 0.31 11 0.03 0.06 0.09 0.11 0.03 0.25 0.30 12 0.050.13 0.12 0.17 0.05 0.22 0.29 13 0.06 0.05 0.08 0.12 0.06 0.23 0.27 140.03 0.08 0.09 0.09 0.03 0.28 0.25 15 0.08 0.03 0.10 0.09 0.08 0.23 0.2416 0.05 0.12 0.02 0.02 0.05 0.21 0.26

[0144] TABLE 2 Pattern recognition deviation rate (%) Example 1 0.32Example 2 0.86 Example 3 0.45 Example 4 0.76 Example 5 0.32 Comparative2.51 Example 1 Comparative 3.68 Example 2

[0145] According to the above-described results, the following wasfound.

[0146] In Examples 1 to 5, the surface resistance distribution of thetransparent conductive layer in the slit roll of the transparentconductive film is uniform in both the longitudinal and lateraldirections. Therefore, for example, input patterns can be accuratelyrecognized by the touch panel produced from the slit roll of thetransparent conductive film of Example 1.

[0147] In contrast, the surface resistance distribution of thetransparent conductive layer of Comparative Example 1 had insufficientuniformity in the longitudinal direction and that of Comparative Example2 had insufficient uniformity in the lateral direction. Therefore, forexample, the touch panel produced from the slit roll of the transparentconductive film of Comparative Examples 1 or 2 had a high patternrecognition deviation rate and was thus inadequate.

INDUSTRIAL APPLICABILITY

[0148] A transparent conductive film roll having quality, such assurface resistance or the like, which is uniform in longitudinal andlateral directions thereof, is obtained, leading to excellent functionalstability, such as less character or pattern recognition deviation rateor the like, when the transparent conductive film roll is used in afinal product, such as a touch panel or the like.

1-12. (Cancelled).
 13. A transparent conductive film roll which isobtained by rolling up a plastic film having a transparent conductivelayer on at least one side thereof, a width thereof being 300 to 1300 mmand a length thereof being 10 to 1000 m, wherein, when a surfaceresistance (Ω/□) of the transparent conductive layer is measured at atotal of 33 points including positions located at a middle in a lateraldirection thereof and any positions located at a distance of from 25 to100 mm from lateral ends thereof, the positions being separated inIntervals of {fraction (1/10)} of a full length in a longitudinaldirection thereof, a distribution uniformity D of the surface resistanceis 0.20 or less, the distribution uniformity D being represented byexpression (1): D=(Rmax−Rmin)/(Rmax+Rmin)  (1) where Rmax and Rminrepresent a maximum and minimum of surf ace resistance measurementvalues at the 33 points, respectively.
 14. A transparent conductive ffilm roll according to claim 13, wherein the plastic film has athickness of 10 to 300 Km.
 15. A transparent conductive film rollaccording to claim 13, wherein a curable resin cured material layer oran inorganic thin film layer is provided between the plastic film andthe transparent conductive layer.
 16. A transparent conductive film rollaccording to claim 13, wherein the transparent conductive layer Is madeof indium-tin mixed oxide or tin-antimony mixed oxide.
 17. A transparentconductive film roll according to claim 13, wherein the transparentconductive layer has a thickness of 4 to 800 nm.
 18. A touch panelcomprising a pair of panel plates having a transparent conductive layer,the panel plates being disposed via a spacer so that the transparentconductive layers face each other, wherein at least one of the panelplates is a transparent conductive film obtained by cutting atransparent conductive film roll according to claim
 13. 19. A method forproducing a transparent conductive film roll having a transparentconductive layer on at least one side thereof using a rolled-up filmforming device, wherein the rolled-up film forming device has anon-contact surface resistance measuring device therewithin, a surfaceresistance of the transparent conductive layer is sequentially measuredin line at a plurality of positions in each of longitudinal and lateraldirections of the film while forming the transparent conductive layer,and conditions for forming the transparent conductive layer areregulated so that the surface resistance thereof is uniformlydistributed, and the non-contact surface resistance measuring devicemainly comprises an eddy current generating section which is placed at apredetermined distance from the transparent conductive layer, faces thetransparent conductive layer and flows an eddy current in thetransparent conductive layer, an eddy current detecting section which isseparated from the transparent conductive layer and detects the eddycurrent flowing through the transparent conductive layer, a temperaturedetecting section which detects a temperature of the eddy currentgenerating section or the eddy current detecting section, and acalculating means which calculates the surface resistance of thetransparent conductive layer based on a result of detection by the eddycurrent detecting section and a result of detection by the temperaturedetecting section where a voltage applied to the eddy current generatingsection is constant, wherein, when the result of detection by thetemperature detecting section is deviated from a reference temperature,the calculating means calculates an amount of an increase or decrease inthe eddy current caused by the deviation from the reference temperatureand adds or subtracts the amount of the increase or decrease in the eddycurrent to or from the result of detection by the eddy current detectingsection to correct the value of the eddy current and calculates thesurface resistance of the transparent conductive layer based on thecorrected value of the eddy current.
 20. A transparent conductive filmproduction method according to claim 19, wherein the non-contact surfaceresistance measuring device further comprises a separation distancesensor, and the calculating means further corrects a result ofcalculation based on a calibration curve indicating a relationshipbetween surface resistance and separation distance.
 21. A transparentconductive film roll production method according to claim 19, wherein aplurality of non-contact surface resistance measuring devices areprovided in the lateral direction of the film.
 22. A transparentconductive film roll production method according to claim 19, whereinthe non-contact surface resistance measuring device is continuouslyreciprocated in the lateral direction of the film.
 23. A non-contactsurface resistance measuring device, mainly comprising an eddy currentgenerating section which is placed at a predetermined distance from thetransparent conductive layer, faces the transparent conductive layer andflows an eddy current In the transparent conductive layer, an eddycurrent detecting section which is separated from the transparentconductive layer and detects the eddy current flowing through thetransparent conductive layer, a temperature detecting section whichdetects a temperature of the eddy current generating section or the eddycurrent detecting section, and a calculating means which calculates asurface resistance of the transparent conductive layer based on a resultof detection by the eddy current detecting section and a result ofdetection by the temperature detecting section where a voltage appliedto the eddy current generating section is constant, wherein, when theresult of detection by the temperature detecting section is deviatedfrom a reference temperature, the calculating means calculates an amountof an increase or decrease in the eddy current caused by the deviationfrom the reference temperature and adds or subtracts the amount of theincrease or decrease in the eddy current to or from the result ofdetection by the eddy current detecting section to correct the value ofthe eddy current and calculates the surface resistance of thetransparent conductive layer based on the corrected value of the eddycurrent.
 24. A non-contact surface resistance measuring device accordingto claim 23, wherein the number of the temperature detecting sections issmaller than the number of the eddy current generating sections.
 25. Anon-contact surface resistance measuring device according to claim 23,wherein the non-contact surface resistance measuring device furthercomprises a separation distance sensor, and the calculating meansfurther corrects a result of calculation based on a calibration curveindicating a relationship between surface resistance and separationdistance.